Method of preparing an &#39; -amino-&#39;7 -lactam

ABSTRACT

There is provided an improved method of producing an Alpha amino- omega -lactam of the formula   BY THE Beckmann rearrangement of an Alpha -aminocycloalkanone oxime of the formula   WHEREIN N IS AN INTEGER BETWEEN 0 AND 12, THE IMPROVEMENT COMPRISING THE STEPS OF: 1. DISSOLVING, IN A FIRST REACTION STEP, THE OXIME OR A MIXTURE CONTAINING THE OXIME AND AN ACID SALT THEREOF, AND NH4Cl in sulfuric acid having a concentration of about 100 to 110% (i.e., water-free sulfuric acid containing up to 45% by weight of free SO3) while maintaining a temperature in the first reaction step in the range of about -5* to 35*C; 2. removing the evolved HCl gas formed in the first reaction step; 3. ADDING, IN A SECOND REACTION STEP THE SOLUTION FROM THE FIRST REACTION STEP TO SULFURIC ACID OF A CONCENTRATION OF ABOUT 100 TO 110% OR TO A Beckmann rearrangement mixture derived from said oxime containing sulfuric acid of such concentration while maintaining a temperature in said second reaction step below about 100*C by cooling, the rate of addition of the solution and the amount of cooling being adjusted to maintain the temperature in said range, whereby a rearrangement mixture is formed; 4. REMOVING THE EVOLVED HCl gas formed in the second reaction step; and 5. STRIPPING RESIDUAL HCl from the rearrangement mixture, whereby a lactam solution substantially free of HCl is formed.

United States Patent [191 Fuhrmann et al.

[4 1 Sept. 9, 1975 METHOD OF PREPARING AN a-ANIINO-w-LACTAM [75]Inventors: Robert Fuhrmann, Morris Plains;

John Pisanchyn, Morristown, both of NJ.

[73] Assignee: Allied Chemical Corporation, New

York, NY.

22 Filed: Nov. 22, 1974 211 App]. No.: 526,281

[52] US. Cl 260/2393 R; 260/2393 A;

Cl. C07D 223/12; C07D 211/76; CO7D 207/26 [58] Field of Search...260/239.3 R, 239.3 A, 293.86, 260/3265 FL [51] Int.

[56] References Cited UNITED STATES PATENTS 3,641,003 2/l972 Ito et al260/2393 R Primary Examiner-Norma S. Milestone Assistant Examiner-RobertT. Bond Attorney, Agent, or Firm-Roger H. Criss; Arthur J. Plantamura[57] ABSTRACT There is provided an improved method of producing ana-amino-w-lactam of the formula I W Z HN (CH2 n by the Beckmannrearrangement of an a-aminocycloalkanone oxime of the formula r jwNH (CHn wherein n is an integer between 0 and 12, the improvement comprisingthe steps of:

1. dissolving, in a first reaction step, the oxime or a mixturecontaining the oxime and an acid salt thereof, and NHqCl in sulfuricacid having a concentration of about 100 to 110% (i.e., water-freesulfuric acid containing up to 45% by weight of free $0 whilemaintaining a temperature in the first reaction step in the range ofabout 5 to 35C;

2. removing the evolved HCl gas formed in the first reaction step;

4. removing the evolved HCl gas formed in the second reaction step; and

5. stripping residual HCl from the rearrangement mixture, whereby alactam solution substantially free of HCl is formed.

12 Claims, N0 Drawings METHOD OF PREPARING AN a-AMlNO-w-LACTAMBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to a process of preparing an a-arnino-m-lactam by the Beckmannrearrangement of an a-amino-cycloalkanone oxime. The invention isparticularly applicable to the Beckmann rearrangement ofa-aminocyclohexanone oxime to a-amino-ycaprolactam.

2. Description of the Prior Art It is known that a-amino-w-lactams areobtained by the Beckmann rearrangement of an ok-aminocycloalkanoneoxime. As the Beckmann reagent (transposition agent) in suchrearrangement, there has been suggested sulfuric acid, fuming sulfuricacid, chlorosulfonic acid, sulfur trioxide, liquid S containing S0.polyphosphoric acid optionally containing catalytic amounts ofhydrochloric acid, mixtures containing sulfuric and hydrochloric acidand the, like. For example, it is known that a-amino-e-caprolactarn(ACL) is formed by the Beckmann rearrangement of a-amino-cyclohexanoneoxime (ACO) free base or its salt utilizing the above reagents. The ACLso formed can be utilized to prepare the basic amino acid lysine, whichisan excellent protein supplement and demand for which has beenincreasing rapidly.

The AC0 to be rearranged may be produced by several processes such asdirect amination of the dimer of chloro-nitrosocyclohexane or theamination of 2- chlorocyclohexanone in the presence of hydroxylamine.Both of these reactions produce ACO free base as well as NH Clby-product plus impurities. It has heretofore been considered necessarythat the NH Cl must either be removed from the ACO free base prior tothe Beckmann rearrangement reaction or the ACO-NH CI mixture must beconverted via an exchange reaction to AC0 hydrochloride (ACO.HC1) andammonia which is separated from the system.

It has been postulated that only the synform of the ACO is rearranged toa-amino'ecaprolactam and that the anti-form is rearranged toe-amino-e-caprolactam, which is not the desired product for use in theproduction of lysine and complicates purification of such desiredproduct. ACO and other a-aminocycloalkanone oximes exist as the antiandsynform of the isomer, depending upon the relative position of the OHradical to that of the amino radical as shown below:

HO OH II II OM1 0- NH Anti-form Syn-form The syn-isomer has never beenisolated and its physical properties are still unknown. I

it has been suggested in Japanese patent publication 48-10788 1973) tocarry out the Beckmann rearrangement of AC0 to ACL by first convertingthe anti form of AC0 to the synform in sulfuric acid to form the synform of ACO-sulfate exclusively and then heating the reaction mixture toobtain the desired Beckmann rearrangement. That is, the Beckmannrearrangement process therein suggested comprises a three-step process:first, dissolving the ACO in at least 5 3 moles of sulfuric acid of aconcentration of l00-l05% maintained at a temperature of 0 to 60C,second, holding the liquid at such temperature for a long contact time(1 to 2 hours) and third, heating the liquid, for example, to 80C for 40minutes, to obtain the rearranged product. The rearranged product isthereafter neutralized, ACL is extracted out with ethanol and isconverted to ACL hydrochloride which crystallizes out.

However, it has been found that in carrying out the third step of suchprocess, that is heating of the cold sulfuric acid solution, anuncontrollable exotherm occurs. For instance, a temperature of over 120Cis.

reached within a few seconds even with cooling. Consequently, thissuggested process does not appear to be commercially attractive due tothe large cooling requirements and danger of explosion. Moreover, therelatively long low temperature contact time and the separation of theACO in its free base or salt form from Nl-l Cl (as explained above) arefurther process disadvantages.

Additionally, as mentioned above, subsequent to the Beckmannrearrangement of a-aminocycloalkanone oximes, such as ACO, the resultingmixture is conventionally neutralized (e.g., with ammonia) to form thefree base lactam, ACL in the case of ACO, along with ammonium sulfateby-product, and the ACL is separated by extraction or like procedures,with the ammonium sulfate being filtered off. The by-product ammo niumsulfate has commercial value as a fertilizer but such value isdiminished for certain uses if the sulfate salt is contaminated byammonium chloride. It has been found that the ammonium sulfateby-product formed by neutralizing the resulting reaction product of theaforesaid Japanese publication contains undesirable amounts of NH Cl.Moreover, the NH CI so formed may interfere with the subsequentextraction of ACL.

Summary of the Invention In accordance with this invention, there isprovided an improved method of producing an a-amino-mlactam of theformula by the Beckmann rearrangement of an a-aminocycloalkanone oximcof the formula on S N ll

wherein n is an integer between Oand 12, the improvement comprising thesteps of:

l, dissolving, in a first reaction step, the oxime or a mixturecontaining the oxime and an acid salt thereof,

and Nl-l Cl in'sulfuric acid having a concentration of 5 about 100 to110% (i.e., water-free sulfuric acid containing up to 45% by weight offree $05) while maintaining a temperature in the first reaction step inthe range of about 5 to 35C;

2. removing the evolved Hcl gas formed in the first reaction step; i

3. adding, in a second reaction step, the solution from the firstreaction step to sulfuric acid of a concentration of about 100 to 1 orto a Beckmann rearrangement mixture derived from said oxime containingsulfuric acid of such concentration while maintaining a temperature insaid second reaction step below about 100C by cooling, the rate ofaddition'of the solution and the amount of cooling being adjusted tomaintain the temperature in said range, whereby a rearrangement mixtureis formed;

4. removing the evolved HCl gas formed in the second reaction step; and

5. stripping residual HCl from the rearrangement mixture, whereby alactam solution substantially free of HCl is formed. I

r The process of this invention provides a manner of obtaining ana-amino-co-lactam, such as ACL, which is substantially free of HCl, doesnot require purification of the oxime in that the oxime in its crudeform (that is, together with Nl-l Cl and optionally with itshydrochloride) can be employed in the rearrangement reaction, does notrequire a separate low temperature reaction step, provides acontrollable high temperature rearrangement step and a substantiallychloride-free ammonium sulfate by-product. Accordingly, the presentinvention provides a more economical route to the pro-' duction ofa-aminoma-lactams from a-aminocycloalkanone oximes than heretoforesuggested.

Description of the Preferred Embodiments The starting material for theprocess of the invention is an a-aminocycloalkanone oxime of the formulawherein n is an integerfrom 0 to 12, preferably 1 to 8 and mostpreferably 2 (i.e., oz-aminocyclohexanone oxime). The oxime need not beseparated into its synor antiforms and a separate process step forisomerization from antito synis not required; the designation in theabove formula is intended to denote either form of the isomer. Salts ofthe oxime may be employed in addition to the free base form. Such saltsinclude the hydrochloride, sulfate, acetate and other acid salts. Theoxime is prefereably in its free base form or admixed of theseprocedures produce the oxime in its free base form, NH C1 by-product andimpurities; the oxime may be converted to its hydrochloride form by theexchange reaction in aqueous medium:

Amino Oxime NH Cl 2 Amino Oxime.l-1Cl NH,

The oxime in its free base form together with NH Cl is herein referredto as crude oxime. Crude oxime without purification may be directlyutilized in the Beckmann rearrangement process of this invention and itis preferred to utilize such material. It should be understood, however,that the oxime may be alternatively be first separated from NH C1 butthat such purification is not required inthe present process.

The mol ratios of the NH Cl to the oxime used herein are in the range ofabout 0.3 to 2, preferably about 0.5 to 1, mols of NH Cl per mol ofoxime. When the mol ratio is below about 0.3: 1, or above about 2: 1 theyield is substantially reduced.

The oxime and the NH C1 together as a mixture or separately, if desired,is added to a first reaction stage, which comprises one or more reactorsconstructed of suitable inert material such as glass, stainless steel,

glass-lined steel and the like. The first reaction stage containssulfuric acid of a concentration in the range of about to preferablyabout 100.5 to 103% and is cooled by suitable cooling means. Atconcentra-' tions below about 100% the yield is substantially re-' ducedwhereas at concentrations above about 110%, undesirable side reactionsoccur and recovery of HCl is difficult. The oxime and the NH Cl aredissolved in the sulfuric acid with the temperature being maintained inthe range of about 5 to 35C, preferably about 5 to 20C. At thistemperature, the rearrangement reac tion occurs only relatively slowly.Upon dissolution, hydrogen chloride gas is evolved from the solution.The reactor(s) is provided with a vent or other opening through whichthe evolved gas is removed and recovered.

The amount of oxime/Nl-LC] added to the sulfuric acid may be such as toprovide from about 3 to 10, preferably about 3.5 to 8.5 mols of H 80 permol of the oxime. The resulting solution is added within a short periodof time, preferably immediately, after its formation to a secondreaction stage since it has been found that there is no advantage inmaintaining the oxime/NH,C1 solution at the low temperature for anyappreciablc length of time. The solution may be added to the nextreaction stage within a short period of time, with no additionalresidence time, if desired.

The second reaction stage may comprise one or more reactors whichcontain sulfuric acid or a rearrangement mixture comprising the oximesalts, HCl, NH, ions, sulfuric acid and rearrangementproducts (includingthe aminolactam acid salt). In either case, the second reaction stagecontains sulfuric acid. The use of a rearranged mixture is especiallyadvantageous when carrying out the process of this invention on acontinuous basis whereas the use of sulfuric acid alone may beadvantageous for batch processes. The sulfuric acid concentration in thesecond reaction stage should likewise be in the range of about 100 to lpreferably 100.5 to 103%. Additional sulfuric acid may be added to aprevious rearrangement mixture so that the mol ratio of the oxime to H80, is within the desired range in the second reaction stage. It isagain desired that this mol ratio should be in the range of about?) to10, preferably about 3.5 to 8.5, mols of H SO per mol of the oxime forthe rearrangement to occur. The second reaction stage is maintained at amaximum temperature of about 100C, preferably about 50 to 100C, morepreferably about 60 to 90C. by conventional cooling means. If thetemperature exceeds 100C, excessive foaming and yield loss occurs.Temperatures below about 50C can be employed but are not generallydesirable since the rearrangement reaction is slower.

The rate of addition of the solution from the first reaction stage tothe second reaction stage and the rate of cooling of the second reactionstage are adjusted to maintain the desired temperatures. The reactor(s)of the second reaction stage is also fitted with a vent or other openingand is constructed of the same or similar materials mentioned withrespect to the reactors of the first reaction stage. Hydrogen chloridegas is also evolved during the rearrangement reaction and it is removedfrom the reactor( s) through the vent or opening and is recovered.

The contact time in the second reaction stage is also fairly short anddepends upon the temperature employed, the mol ratios, and otherfactors, but is generally sufficient to effect at least about 99%conversion to the lactam. Preferably, reaction times are in the range ofabout 2 minutes to 3 hours, more preferably about 10 to 60 minutes. TheBeckmann rearrangement reaction occurs very fast; for example, at 50C,the reaction time may be in the range of about minutes. At 80C, thereaction time is less than about 5 minutes.

The total amount of HCl removed from the first and second reactorsgenerally ranges from about 0.5 to 0.8 mols of HCl per mol of ACL.

Following rearrangement in the second reaction stage, the liquidcontaining the rearranged mixture of the lactam (as a sulfate salt), NH,ions, residual HCl and other by-products and impurities is fed to astripping chamber wherein the residual HCl is stripped from the liquid.The stripping operation may be performed utilizing a vacuum or an inertgas such as nitrogen. Thin film or wiped film flash evaporators may beemployed for this purpose.

The lactam solution that is obtained after the stripping operation issubstantially free of HCl. By substantially free" it is meant that thereare less than about 0.15 mols of HCl per mol of lactam, preferably lessthan about 0.10 mols, more preferably less than about 0.05 mols, of HClper mol of lactam in the solution. That is, substantially all of the theresidual HCl present, about 0.2 to 0.5 mols per mol of ACL, iseliminated. The lactam in the resulting solution is in its acid saltform, such as the sulfate. The lactam in its free base form can beobtained by neutralizing with, for example, ammonia followed byseparation utilizing extraction or the like procedures. For example, thelactam solution can be contacted with a solvent while simultaneouslyneutralizing with ammonia to form the free base lactam in such solvent.The free base can thereafter be obtained by conventional procedures suchas crystallization, extraction, distillation and the like or it may beconverted to a salt, such as the hydrochloride, by known procedures.

The yields of the free base amino lactam, based on the amount of theoxime to be rearranged, in accor dance with the process of thisinvention are high, such as, for example, to 98 percent.

In can be seen that the process of the present invention provides anefficient and economic manner for preparing a-aminow-lactams in highyields. Such high yields are obtainable without the need for separatingammonium chloride from the oxime or formation of the oximehydrochloride. Hence, the evaporation of large quantities of water, theextraction of other impurities and the elimination of the last traces ofmoisture from the ACOLHCl crystals (attendant with the removal ofammonia during the exchange reaction) are not required. Moreover, incarrying out this process, there is better reaction control in therearrangement reaction in that the strong exotherm of the prior art isavoided. Furthermore, the ammonium sulfate byproduct that is obtained ismore valuable than the di lute aqueous ammonia streams resulting fromother suggested processes and the ammonium sulfate is not contaminatedby ammonium chloride impurities. As pointed out above, the ACL formed inaccordance with this invention can be used to prepare lysine.

To further describe the process of this invention, the followingnon-limiting examples are given.

EXAMPLE 1 Into ajacketed 100 cc flask fitted with a stirrer,thermometer, nitrogen gas inlet and charge port was added sulfuric acidof a concentration of 100 to 102.5%. The temperature was reduced bycirculating cooled water through the jacket. While a stream of drynitrogen gas was maintained in the flask, a mixture of ACO and ammoniumchloride was added through a charging port in the flask with stirring.Evolved HCl gas was permitted to escape into a silicone oil bubbler.After a period of time to insure complete dissolution of the solids, thesolution was added to a 100 cc flask connected to a bottom outlet of thefirst flask. The lower flask was provided with a magnetic bar stirrerand the temperature was controlled by an oil bath with any intermittentcooling provided by an ice bath. A desired amount of sulfuric acid wasplaced in the lower flask and brought to the desired temperature.Addition of the solution from the first flask was commenced under a drynitrogen gas atmosphere with stirring. HCl gas evolved from the secondflask was permitted to escape through a silicone oil bubbler. As thereaction is exothermic, within a short time cooling was required tomaintain the desired temperature.

After the reaction was completed, residual l-lCl gas was eliminated fromthe reaction mixture by applying a vacuum to the second flask withcontinuous stirring.

HClfl-ashing time was in the order of 30 to 60 minutes.

After completion of the HCl elimination stage, the

. reaction mixture was weighed and neutralized by gradammonia throughthe solution. The resulting slurry of ammonium sulfate was thoroughlystirred during the addition and the temperature was maintained at to Cby cooling and controlling the rate of addition. The amount of solventrequired in the neutralization step depended somewhat on the sulfuricacid/ACO ratio used in the rearrangement step, but the concentration ofthe resulting ACL solutions was about 4 to 15%. The neutralized slurrieswere than filtered and the inorganic salts reslurried with additionalsolvent to remove ACL still contained as mother liquor in the filtercake. Generally, three washes of 200 cc of solvent (per millimol chargeof ACO) were used. The washes were combined with the original filtrateand concentrated on a flash evaporator under a slight vacuum. Yieldswere determined by vapor chromatographic analysis and gravimetricdetermination of ACL.HC1.

The inorganic salts were dried and weighed and residual chorine ion wasdetermined in the inorganic salt by potentiometric titration. Theresults are shown in Table 1, below. Comparative examples are shown inTable 2, below.

monium chloride and ACO, a reaction temperature of about 80C and vacuumflashing of HCl at 0.5 to 15 mm Hg. The residual chloride ion in theinorganic salts was, respectively, 4.3, 0.7 and 2.0 mol percent based onthe mols of ACL. Examples 4-6 show similar yields with reducedsolubilization, addition and reaction times. Examples 7-10 demonstratethat high yields of ACL can be obtained with addition times to theBeckmann reactor ranging from 9 to 45 minutes.

Comparative Examples 1 1 and 14 (Table 2) show that yields are notincreased by using ammonium chlo- TABLE 1 EXAMPLE NO. 1 2 3 4 5 6 7 8 9l0 Soluhilization Temp.,( 8-10 8-10 10-15 12-17 10-14 0 10-17 11-1412-14 8-10 Time. Hours* 3.5 3 5 3.5 1.5 2.8 1.1 2.6 3.0 3.0 5.0 initialH SO,/ACO Mol Ratio 4 8 5.1 4.95 6.7 7 l 7.2 5.35 4.49 4.85 6.9NH,C1/ACO Mol Ratio 1 l l 1 1 l l I 1 1 Addition Time to Reactor. 60 6020 l2 l2 9 36 45 45 Min.

Reaction Temp..C 78-83 80-83 805 78-82 -80 70-80 80L; 78:4 79:3 8015Time. Min. 40 40 40 42 20 42 42 42 42 42 Final H SO /ACO Mol Ratio 6.76.0 6.0 7.8 7.9 6.03 6.27 603 6.10 8.45 HCl Flashing Temp C 78-80 78-80-82 65 72.5 77 none none none none Vacuum. mm Hg 12-15 12-15 0.5 0.5 5Flashing Time. Min. 30 60 60 60 30 30 Residual Cl ion. Mo! '7( 4.3 0.72.0 ACL Yield. Mo] "/1 87 90 91 96.0 84.2 97.0 94.8 94.3 92.0 950Neutralization Solvent iso-PrOH Glyme Glyme Glyme Glyme Glyme (ilymeGlyme Dioxane *lncludes addition time of ACO NH Cl solids as well astime required to obtain clear solution.

**|2l5 mm Hg for 15 min. and 0.5-1.0 mm Hg for 45 min. **"3 partstriehloroeth \lene to 1 part isopropanol.

TABLE 2 EXAMPLE NO. 11 12 13 14 15 16 17 Soluhilization Temp.C. 10-1610-15 10-15 10-16 10-15 12-15 12-15 Time, hours* 2.3 1.5 3.0 5.7 3.0 4.04.2 initial H. .SO,/ACO M01 Ratio 5.09 4.09 5.16 6.67 7.0 4.67 4.0lsomerization Time, hours 2.0 2.0 2.0 none 2.0 1.0 none Temp.C. 10-1610-16 10-15 10-15 12-15 NH Cl/ACO Mol Ratio 0 0.5 l 3.0 l l 1 AdditionTime to Reactor, 15 30 30 30 none 45 min.

Reaction Temp.,C. 79.5:25 79.5115 82.5-12.5 795:2.5 22-26 46:2 -95 Time,min. 42 42 42 42 1 70 42 Final H SOJACO M01 Ratio 6.72 6.44 7.03 8.187.01 6.9 5.10 Residual Chloride lon, 47.6 37.6 18.4

M01 /1 ACL Yield. M01 /1 86.1 91.8 91.6 64.0 90.8 96.0 90.0

*lneludes addition time of ACO NH,C1 solids as well as time required toobtain a clear solution. Neutrali/ation solvent for Examples 11-17 wasglyme.

The results shown in Table 1 demonstrate the high yields of ACL that canbe obtained while providing an ammonium sulfate by-product containing aminimum amount of ammonium chloride. Examples 1, 2 and 3 show thatyields of 87, 90 and 91 mol percent, respectively, of ACL can beobtained without an isomerization step and by utilizing an equimolarmixture of ammols of ACL, 47.6 mol percent at a reaction temperature ofabout room temperature, 37.6 mol percent at about 46C and is still 18.4mol percent when the reaction temperature is raised to 9()95C (Example17). However, in Example 17, heavy degassing was observed. The residualchloride ion content of Examples 15-17 is dramatically higher than thatof Examples 1-3 wherein HCl was eliminated from the Beckmann reactor.

It is to be understood that variations and modifications of the presentinvention may be made without departing from the scope of the invention.It is also to be understood that the scope of the invention is not to beinterpreted as limited to the specific embodiment disclosed herein, butonly in accordance with the appended claims when read in light of theforegoing disclosure.

We claim:

1. In a method of producing an a-amino-w-lactam of the formula by theBeckmann rearrangement of an a-aminocycloalkanone oxime of the formulawherein n is an integer between 0 and 12, the improvement comprising thesteps of 1. dissolving, in a first reaction step, said oxime or amixture containing said oxime and an acid salt thereof, and NH Cl insulfuric acid of a concentration of about 100 to l 10% while maintaininga temperature in said first reaction step in the range of about 5 to35C;

2. removing the evolved HCl gas formed in said first reaction step;

3. adding, in a second reaction step, the solution from said firstreaction step to sulfuric acid of a concentration of about 100 to 110%or to a Beckmann rearrangement mixture derived from said oximecontaining sulfuric acid of said concentration while maintaining atemperature in said second reaction step below about C by cooling, therate of addition of said solution from said first reaction step and theamount of cooling being adjusted to maintain said temperature in saidrange, whereby a rearrangement mixture is formed;

4. removing the evolved HCl gas from said second reaction step; and

5. stripping residual l-lCl from said rearrangement mixture whereby alactam solution substantially free of HCl is formed.

2. The process of claim 1 wherein said second reaction step comprisesadding said solution to said Beckmann rearrangement mixture.

3. The process of claim 1 wherein said temperature in said secondreaction step is maintained in the range of about 50 to 100C.

4. The process of claim 1 wherein said oxime and ammonium chloride areadded in said first step to said sulfuric acid as a mixture, saidmixture resulting from the preparation of said oxime without separationof the ammonium chloride produced in said preparation.

5. The process of claim 1 wherein n is an integer from 1 to 8.

6. The process of claim 1 wherein said a-aminocycloalkanone oxime isa-aminocyclohexanone oxime and said a-amino-w-lactam isa-amino-e-caprolactam.

7. The process of claim 4 wherein said a'aminocycloalkanone oxime isa-aminocyclohexanone oxime and said a-amino-w-lactam isoz-amino-e-caprolactam.

8. The process of claim 1 wherein the mo] ratio of said oxime toammonium chloride which is added in said first reaction step is in therange of about 0.5 to 2 mols of NH Cl per mol oxime.

9. The process of claim 1 wherein the mol ratio in said second reactionstep of sulfuric acid to said oxime is in the range of about 3 to it).

10. The process of claim 1 wherein the contact time in said secondreaction step is sufficient to convert about 99% of said oxime to saidlactam.

11. The process of claim 1 wherein said residual HCl is stripped byvacuum or gas stripping.

12. The process of claim 1 wherein said temperature in said firstreaction step is in the range of about 5 to 25C.

1. DISSOLVING, IN A FIRST REACTION STEP, SAID OXIME OR A MIXTURECONTAINING SAID OXIME AND AN ACID SALT THEREOF, AND NH4CI IN SULFURICACID OF A CONCENTRATION OF ABOUT 100 TO 110% WHILE MAINTAINING ATEMPERATURE IN SAID FIRST REACTION STEP IN THE RANGE OF ABOUT -5* TO35*C,
 1. IN A METHOD OF PRODUCING AN A-AMINO-W-LACTAM OF THE FORMULA 2.REMOVING THE EVOLVED HCI GAS FORMED IN SAID FIRST REACTION STEP,
 2. Theprocess of claim 1 wherein said second reaction step comprises addingsaid solution to said Beckmann rearrangement mixture.
 2. removing theevolved HCl gas formed in said first reaction step;
 3. adding, in asecond reaction step, the solution from said first reaction step tosulfuric acid of a concentration of about 100 to 110% or to a Beckmannrearrangement mixture derived from said oxime containing sulfuric acidof said concentration while maintaining a temperature in said secondreaction step below about 100*C by cooling, the rate of addition of saidsolution from said first reaction step and the amount of cooling beingadjusted to maintain said temperature in said range, whereby arearrangement mixture is formed;
 3. The process of claim 1 wherein saidtemperature in said second reaction step is maintained in the range ofabout 50* to 100*C.
 3. ADDING IN A SECOND REACTION STEP, THE SOLUTIONFROM SAID FIRST REACTION STEP TO SULFURIC ACID OF A CONCENTRATION OFABOUT 100 TO 110% OR TO A BECKMANN REARRANGEMENT MIXTURE DERIVED FROMSAID OXIME CONTAINING SULFURIC ACID OF SAID CONCENTRATION WHILEMAINTAINING A TEMPERATURE IN SAID SECOND REACTION STEP BELOW ABOUT 100*CBY COOLING, THE RATE OF ADDITION OF SAID SOLUTION FROM SAID FIRSTREACTION STEP AND THE AMOUNT OF COOLING BEING ADJUSTED TO MAINTAIN SAIDTEMPERATURE IN SAID RANGE, WHEREBY A REARANGEMENT MIXTURE IS FORMED, 4.The process of claim 1 wherein said oxime and ammonium chloride areadded in said first step to said sulfuric acid as a mixture, saidmixture resulting from the preparation of said oxime without separationof the ammonium chloride produced in said preparation.
 4. removing theevolved HCl gas from said second reaction step; and
 4. REMOVING THEEVOLVED HCI GAS FROM SAID SECOND REACTION STEP, AND
 5. STRIPPINGRESIDUAL HCI FROM SAID REARRANGEMENT MIXTURE WHEREBY A LACTAM SOLUTIONSUBSTANTIALLY FREE OF HCI IS FORMED.
 5. stripping residual HCl from saidrearrangement mixture whereby a lactam solution substantially free ofHCl is formed.
 5. The process of claim 1 wherein n is an integer from 1to
 8. 6. THE PROCESS OF CLAIM 1 WHEREIN SAID A-AMINO-CYCLOALKANONE OXIMEIS A-AMINOCYCLOHEXANONE OXIME AND SAID AAMINO-W-LACTAM ISA-AMINO-C-CAPROLACTAM.
 7. The process of claim 4 wherein said Alpha-amino-cycloalkanone oxime is Alpha -aminocyclohexanone oxime and saidAlpha -amino- omega -lactam is Alpha -amino- epsilon -caprolactam. 8.The process of claim 1 wherein the mol ratio of said oxime to ammoniumchloride which is added in said first reaction step is in the range ofabout 0.5 to 2 mols of NH4Cl per mol oxime.
 9. The process of claim 1wherein the mol ratio in said second reaction step of sulfuric acid tosaid oxime is in the range of about 3 to
 10. 10. The process of claim 1wherein the contact time in said second reaction step is sufficient toconvert about 99% of said oxime to said lactam.
 11. The process of claim1 wherein said residual HCl is stripped by vacuum or gas stripping. 12.The process of claim 1 wherein said temperature in said first reactionstep is in the range of about -5* to 25*C.